1. Field
The present invention generally relates to photovoltaics, and more particularly to a method and system for covering photovoltaic cells.
2. Discussion of Related Art
The efficiency with which a solar-to-electricity power conversion device can convert sunlight into electricity is determined, in part, by how well the device responds to the spectral characteristics of the solar flux. Photovoltaic devices, for example, are capable of absorbing light, at varying efficiency, over a large part of the solar spectrum. While some of the solar photons are efficiently converted to electricity, other photons impart only some of their energy to electric energy, and others simply heat the photovoltaic device.
Photovoltaic devices are capable of converting only a fraction of solar photons into electricity. Thus, for example, silicon photovoltaic cells can convert light from approximately 0.3 μm to approximately 1.1 μm into electron-hole pairs, which may be used to generate electricity. Photons having longer wavelengths have an energy that is less than the band gap energy of silicon photovoltaic cells, and are not absorbed. Photons having a wavelength below the upper limit but that are not converted to electricity are converted to heat, which raises the temperature of the photovoltaic device. In addition, some of the energy of photovoltaically converted photons also appears as heat. Specifically, the difference between the photon energy and the band gap energy is not useful for generating electron-hole pairs and is lost as heat within the photovoltaic device.
There are thus many mechanisms affecting photovoltaic conversion and unwanted heating of photovoltaic devices. There is a need in the art for a photovoltaic device that more efficiently converts the solar flux into useable electricity. There is also a need in the art for a photovoltaic device minimizes the amount of heat generated therein. Such a device should be simple and inexpensive, and compatible with current photovoltaic technology.